[NM021AAB], Technical Note, Thomas Alva Edison, May 21st, 1887


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[NM021AAB], Technical Note, Thomas Alva Edison, May 21st, 1887

Editor's Notes

Dyer Patent-- Improvement in phonographs The object of the invention is to imporve the articularion of the phonograph-- The invention consists of a cylinder of wax or other yielding material such as moulded Kaloin, Camphor Napthaline coated with tin foil or film of gelatin or other smooth Extensible materials so that the surface will be very yielding & yet none of the material of the cylinder shall be cut away-- The invention further consists in causing the reproducing point connected directly to the diaphragm to be given motion not by riding in & out of the indentions bu by electric attraction between The point and the electrified cylinder or point as the case may be. The point does not come in contact with the moving surface but nevertheless it will be given a motion corresponding to Pitch & amplitude of the indentations. The electrification of the point or tin foil surface is accomplished by a small disck of hard rubber or glass provided with a rubber & collector-- The disk being turned simultaneously with the phonograph cylinder-- Any other electrifying device may be used The cylinder of wax or other material is connected to the earth in the usual method in static electric apparatus. The smooth surface of the cylinder is grooved by a grooving tool like a chaser This is in advance of the recording point The recording oint is of chisel shap & indents the apex of the ridge left by the Threading tool-- Thus the record extends outward beyond the general surface of the cylinder & is very susceptible to attraction for the point on the receiving diaphragm claim reproducing from phonograph records by electrification of the record or reproducer or both 2nd Reproducting iwthout contact. 3 The Chisel point. 4-- Cylinder of Wax or other yielding material coated with an extensible material 5 forming a thread or screw & recording on the apex of the ridge betwee 6-- cylinder of yielding material covered with metallic foil-- etc--" [drawings follow]




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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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